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Active control of flexural vibrations in beamsThe feasibility of using piezoelectric actuators to control the flexural oscillations of large structures in space is investigated. Flexural oscillations are excited by impulsive loads. The vibratory response can degrade the pointing accuracy of cameras and antennae, and can cause high stresses at structural node points. Piezoelectric actuators have the advantage of exerting localized bending moments. In this way, vibration is controlled without exciting rigid body modes. The actuators are used in collocated sensor/driver pairs to form a feedback control system. The sensor produces a voltage that is proportional to the dynamic stress at the sensor location, and the driver produces a force that is proportional to the voltage applied to it. The analog control system amplifies and phase shifts the sensor signal to produce the voltage signal that is applied to the driver. The feedback control is demonstrated to increase the first mode damping in a cantilever beam by up to 100 percent, depending on the amplifier gain. The damping efficiency of the control system when the piezoelectrics are not optimally positioned at points of high stress in the beam is evaluated.
Document ID
19880005484
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Gerhold, Carl H. (Texas A&M Univ. College Station, TX, United States)
Date Acquired
September 5, 2013
Publication Date
November 1, 1987
Publication Information
Publication: NASA. Johnson Space Center, NASA(ASEE Summer Faculty Fellowship Program, 1987, Volume 1
Subject Category
Structural Mechanics
Accession Number
88N14866
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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